As far as I know Hyper Threading was just a pre step to the dual core processors. There you have 2 cores but only virtually. CFX never supportet that. Using CFX on (real!) dual core processors (I use a Smithfield) means that single job just uses one core. In the Task Manager you will see that with the 50% load. If you want to use the full processor power you have to run it in parallel: In your example 2 partitions per Cluster-Node.